Light source module and backlight unit having the same

ABSTRACT

A light source including a circuit board, at least one light emitting device mounted on the circuit board by flip-chip bonding or surface mount technology (SMT), and a reflective portion formed on the circuit board and enclosing the light emitting device. The reflective portion formed on the circuit board reflects light emitted from the light emitting device in one direction, to reduce light loss while focusing light in a desired direction.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from and the benefit of Korean PatentApplication No. 10-2013-0132340 filed on Nov. 1, 2013, and No.10-2014-0019740 filed on Feb. 20, 2014 in the Korean IntellectualProperty Office, the entire contents of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a light source module, and moreparticularly, to a light source module having a low profile structurewhile improving an external appearance and luminous efficacy, and abacklight unit including the same.

2. Background

Generally backlight units are widely used for liquid crystal displays orsurface lighting.

Backlight units of liquid crystal displays can be classified into directtype and edge type backlight units according to the locations of thelight emitting devices.

The direct type backlight units have been mainly developed along withproduction of large-size liquid crystal displays having a size of 20inches or more, and include a plurality of light sources under adiffusive plate to directly emit light towards a front side of a liquidcrystal display panel. The direct type backlight units are mainly usedin large-screen liquid crystal displays requiring high brightness due totheir higher light use efficiency as compared to edge type backlightunits.

The edge type backlight units are mainly applied to relatively smallliquid crystal displays such as monitors of laptop computers and desktopcomputers. Such edge type backlight units have good uniformity of lightillumination and a long lifespan, and advantageously permit thicknessreduction of a liquid crystal display.

An edge type backlight unit structure recently proposed in the artincludes a light emitting diode package that advantageously achieves lowpower consumption and has a low profile structure. The light emittingdiode package is mounted on a substrate and disposed inside a backlightunit.

However, an edge type backlight unit including a light emitting diodepackage has a limit in achieving a low profile structure of thebacklight unit. This is due to increased demand for further thicknessreduction that makes it difficult to use highly efficient light emittingdiode chips due to poor heat dissipation of the light emitting diodepackage.

SUMMARY OF THE INVENTION

It is an aspect of the present invention is aimed at providing a lightsource module which is advantageous in achieving high efficiency and aslim structure. In addition, an aspect of the present invention is aimedat providing a light source module having a novel structure allowingapplication of a highly efficient light emitting device while achievinga slim structure.

It is another aspect of the present invention is aimed at providing atechnology capable of achieving a slim structure of a backlight unitwhile enhancing external appearance by reducing a non-display area.

In accordance with one aspect of the present invention, a light sourcemodule includes: a circuit board; at least one light emitting devicemounted on the circuit board by flip-chip bonding or surface mounttechnology (SMT); and a reflective portion formed on the circuit boardand enclosing the light emitting device.

In one aspect, the present invention advantageously minimizes light losswhile allowing light to be focused in a desired direction by thereflective portion formed on the circuit board and reflecting lightemitted from the light emitting device in one direction.

The light emitting device may include a wavelength conversion layercovering a light emitting diode chip and a reflective layer covering aportion of the wavelength conversion layer.

The light emitting device may include a wavelength conversion layercovering at least two light emitting diode chips and a reflective layercovering a portion of the wavelength conversion layer.

The reflective layer may expose one side surface of the wavelengthconversion layer or may expose three adjacent side surfaces of thewavelength conversion layer.

The reflective portion may include an accommodation recess thataccommodates the light emitting device.

The reflective portion may include inner surfaces defined by theaccommodation recess, and the accommodation recess may expose an uppersurface of the light emitting device and may be open at one side thereofto have a light discharge portion, through which light is dischargedoutside.

The inner surface may have a coplanar structure with side surfaces ofthe light emitting device.

The inner surfaces may have an inclined structure.

The inner surfaces may have a curved structure.

The light emitting device may have the same height as or a lower heightthan the height of the reflective portion.

The reflective layer may expose three adjacent side surfaces and anupper surface of the wavelength conversion layer.

The light source module further includes a reflection cover placed onthe light emitting device and covering the reflective portion.

In accordance with another aspect of the present invention, a backlightunit includes: a light guide plate; and a light source module disposedon at least one side of the light guide plate, wherein the light sourcemodule includes: a circuit board; at least one light emitting devicemounted on the circuit board by flip-chip bonding or surface mounttechnology (SMT); and a reflective portion formed on the circuit boardand enclosing the light emitting device.

In one aspect, the present invention has an advantage of minimizinglight loss while allowing light to be focused in a desired direction bythe reflective portion formed on the circuit board and reflecting lightemitted from the light emitting device in one direction.

In addition, in one aspect the present invention can omit a separatestructure such as a reflective housing for focusing light on the lightguide plate by the structure of the reflective portion integrally formedwith the circuit board, thereby improving assembly efficiency whileadvantageously enabling reduction in thickness of the light sourcemodule and a slim structure of the backlight unit together with thelight emitting device which gradually decreases in thickness.

The light emitting device may include at least two light emitting diodechips, a wavelength conversion layer covering the at least two lightemitting diode chips, and a reflective layer covering a portion of thewavelength conversion layer.

The light guide plate may include a light incident area, through whichlight enters the light guide plate, and a light exit area, through whichlight exits the light guide plate; an upper surface of the light guideplate may have a stepped structure; the light incident area may have ahigher thickness than the light exit area; and the stepped structure mayinclude an inclined surface.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate exemplary embodiments of theinvention, and together with the description serve to explain theprinciples of the invention.

FIG. 1 is a sectional view of a light source module according to anaspect of the present invention.

FIG. 2 a is a plan view of the light emitting device shown in FIG. 1 andFIG. 2 b is a sectional view of the light emitting device taken alongline I-I of FIG. 2 a.

FIG. 3 is an exploded perspective view of a display including a smallbacklight unit according to an aspect of the present invention.

FIG. 4 is a sectional view of the display taken along line II-II′ ofFIG. 3.

FIG. 5 is a perspective view of a light source module of FIG. 3.

FIG. 6 is a plan view of a light source module according to an aspect ofthe present invention.

FIG. 7 is a plan view of a light source module according to an aspect ofthe present invention.

FIG. 8 is a perspective view of a light emitting device according to anaspect of the present invention.

FIG. 9 is a plan view of a light source module including the lightemitting device of FIG. 8.

FIG. 10 is a perspective view of a light source module according to anaspect of the present invention.

FIG. 11 is a sectional view of a display including the light sourcemodule of FIG. 10.

FIG. 12 is a sectional view of a display including a light source moduleaccording to an aspect of the present invention.

FIG. 13 and FIG. 14 are an exploded perspective view of a displayincluding a backlight unit according to an aspect of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, exemplary embodiments of the present invention will bedescribed in detail with reference to the accompanying drawings. Itshould be understood that the following embodiments are provided forcomplete disclosure and thorough understanding of the invention by thoseskilled in the art. Thus, it should be understood that the presentinvention is not limited to the following embodiments and may beembodied in different ways. In addition, in the drawings, the shapes ofcomponents may be exaggerated for convenience. Like components will bedenoted by like reference numerals throughout the specification. Itshould be understood by those skilled in the art that variousmodifications, changes, and alterations can be made without departingfrom the spirit and scope of the invention. The scope of the inventionshould be limited only by the accompanying claims and equivalentsthereof.

Hereinafter, the exemplary embodiments of the present invention will bedescribed in detail with reference to the accompanying drawings for easyimplementation of the present invention by those skilled in the art.

FIG. 1 is a sectional view of a light source module according to anaspect of the present invention.

Referring to FIG. 1, the light source module 100 includes a lightemitting device 110 and a circuit board 140.

The circuit board 140 includes substrate pads 141 a, 141 b electricallyconnected to the light emitting device 110 and bumps 150 a, 150 b placedon the substrate pads 141 a, 141 b. The circuit board 140 may be a metalPCB, which is advantageous in heat dissipation, without being limitedthereto. The circuit board 140 may be a rectangular-shaped board havinga major axis and a minor axis.

The light emitting device 110 includes a light emitting diode chip 111,a wavelength conversion layer 120 covering the light emitting diode chip111, and a reflective layer 121 covering the wavelength conversion layer120.

The light emitting diode chip 111 includes a growth substrate 112 and asemiconductor stack 113. The light emitting diode chip 111 may bedirectly placed on the circuit board 140 by flip-chip bonding or may beelectrically connected to the circuit board 140 by surface mounttechnology (SMT). Here, electrode pads 37 a, 37 b exposed on a lowersurface of the light emitting diode chip 111 are electrically connectedto the substrate pads 141 a, 141 b by the bumps 150 a, 150 b,respectively. Since the light source module 100 does not employ a wire,there is no need for a molding section for protection of the wire or forthe partial removal of the wavelength conversion layer 120 to expose thebonding pads. As such, the present disclosure adopts a flip-chip typelight emitting diode chip 111, thereby achieving removal of colordeviation or brightness spots while simplifying a process ofmanufacturing the light source module, as compared with a light sourcemodule adopting a light emitting diode chip using bonding wires.

The wavelength conversion layer 120 covers the light emitting diode chip111. The wavelength conversion layer 120 surrounds upper and sidesurfaces of the light emitting diode chip 111 and contains phosphorstherein. The phosphors can convert wavelengths of light emitted from thelight emitting diode chip 111. The wavelength conversion layer 120 iscoated onto the light emitting diode chip 111 and may cover the upperand side surfaces of the light emitting diode chip 111 in apredetermined thickness. An area of the wavelength conversion layer 120covering the upper surface of the light emitting diode chip 111 may havethe same thickness or a different thickness than the thickness of anarea covering the side surfaces of the light emitting diode chip 111. Inaddition, an area of the wavelength conversion layer 120 covering lightexit faces through which light exits the light emitting diode chip mayhave a different thickness that those of the areas of the wavelengthconversion layer which cover the side surfaces and the upper surface ofthe light emitting diode chip, excluding the light exit faces thereof.

The reflective layer 121 covers upper and side surfaces of thewavelength conversion layer 120 excluding three adjacent side surfacesof the light emitting diode chip 111, which are defined as the lightexit faces EA (only one of which can be seen in the cross-sectional viewof FIG. 1). The reflective layer 121 serves to reflect light subjectedto wavelength conversion by the wavelength conversion layer 120 towardsthe light exit faces. That is, the reflective layer 121 guides light toexit through the three adjacent side surfaces of the light source module100. In the light emitting device 110, the reflective layer 121 isconfigured to expose the three adjacent side surfaces of the wavelengthconversion layer 120 therethrough. However, it should be understood thatthe present invention is not limited thereto. In other embodiments, thelight emitting device 110 may further include a structure through whichonly one side of the wavelength conversion layer 120 is exposed.

The light source module 100 includes a reflective portion 130 formed onthe circuit board 140 and enclosing the light emitting device 110.

The reflective portion 130 has an accommodation recess 131 whichaccommodates the light emitting device 110, and inner surfaces definedby the accommodation recess 130. The accommodation recess 131 exposes anupper surface of the light emitting device 110 and the accommodationrecess is open at one side thereof to provide a light discharge portion137.

The reflective portion 130 may be directly formed on the circuit board140 by depositing and curing a molding resin on the circuit board.Alternatively, the reflective portion 130 may be placed on the circuitboard 140 via a separate bonding member (not shown). The reflectiveportion 130 serves to reflect light emitted from the light emittingdevice 110 towards the light discharge portion 137 and to protect thelight emitting device 110. The reflective portion 130 may have aprofile, the height of which varies depending upon the design of thelight emitting device 110. The reflective portion 130 may have the sameor greater height than the light emitting device 110.

As described above, the light source module 100 includes the lightemitting diode chip 110 mounted on the circuit board 140 by directflip-chip bonding or SMT, thereby providing an advantage of realizinghigh efficiency and small size as compared with general package typelight source modules using wires.

In addition, the light source module 100 is advantageous in terms ofthickness reduction as compared with the general package type lightsource modules.

Further, in the light source module 100, the reflective portion 130 isformed to enclose the light emitting device 110 on the circuit board140, thereby enabling light emitted from the light emitting device to befocused in one direction of the light source module 100.

Referring to FIGS. 2 a and 2 b, the structure of the light emittingdiode chip 111 will be described in more detail.

FIG. 2 a is a plan view of the light emitting device shown in FIG. 1 andFIG. 2 b is a sectional view of the light emitting device taken alongline I-I of FIG. 2 a.

Referring to FIGS. 2 a and 2 b, the light emitting diode chip includesthe growth substrate 112 and the semiconductor stack 113.

The semiconductor stack 113 includes a first conductive typesemiconductor layer 23 formed on the growth substrate 112 and mesas Mseparated from each other on the first conductive type semiconductorlayer 23.

Each of the mesas M includes an active layer 25 and a second conductivetype semiconductor layer 27. The active layer 25 is placed between thefirst conductive type semiconductor layer 23 and the second conductivetype semiconductor layer 27. In addition, reflective electrodes 30 areplaced on the M, respectively.

As shown, the mesas M may have an elongated shape extending in onedirection to be parallel to each other. Such a shape of the mesas cansimplify formation of the mesas M having the same shape in chip areas onthe growth substrate 112.

The reflective electrodes 30 may be respectively formed on the mesas Mafter the mesas M are formed, without being limited thereto.Alternatively, after the second conductive type semiconductor layer 27is grown, the reflective electrodes 30 may be formed on the secondconductive type semiconductor layer 27 before the mesas M are formed.The reflective electrode 30 covers an upper surface of the mesa M andhas substantially the same shape as the shape of the mesa M in top view.

The reflective electrodes 30 include a reflective layer 28 and mayfurther include a barrier layer 29. The barrier layer 29 may cover anupper surface and side surfaces of the reflective layer 28. For example,a pattern of the reflective layer 28 is formed and the barrier layer 29is formed thereon, whereby the barrier layer 29 can be formed to coverthe upper and side surfaces of the reflective layer 28. For example, thereflective layer 28 may be formed through deposition and patterning ofAg, Ag alloy, Ni/Ag, NiZn/Ag, or TiO/Ag layers. The barrier layer 29 maybe formed of Ni, Cr, Ti, Pt, Rd, Ru, W, Mo, TiW or combinations thereof,and prevents diffusion or contamination of metallic materials of thereflective layer.

After the mesas M are formed, an edge of the first conductive typesemiconductor layer 23 may also be etched. As a result, an upper surfaceof the growth substrate 112 can be exposed. The first conductive typesemiconductor layer 23 may have an inclined side surface.

According to various embodiments, the light emitting diode chip 111further includes a lower insulation layer 31 covering the mesas M andthe first conductive type semiconductor layer 23. The lower insulationlayer 31 has openings formed at predetermined locations thereof, toallow electrical connection to the first conductive type semiconductorlayer 23 and the second conductive type semiconductor layer 27therethrough. For example, the lower insulation layer 31 may haveopenings through which the first conductive type semiconductor layer 23is exposed, and openings through which the reflective electrodes 30 areexposed.

The openings may be placed between the mesas M and near the edge of thesubstrate 21, and may have an elongated shape extending along the mesasM. In addition, the openings are placed only above the mesas M to bebiased towards the same ends of the mesas.

The light emitting diode chip 111 includes a current spreading layer 33formed on the lower insulation layer 31. The current spreading layer 33covers the plurality of mesas M and the first conductive typesemiconductor layer 23. In addition, the current spreading layer 33 isplaced within an upper area of each of the mesas (M) and has openingsfor exposing the reflective electrodes. The current spreading layer 33may form an ohmic contact with the first conductive type semiconductorlayer 23 through the openings of the lower insulation layer 31. Thecurrent spreading layer 33 is insulated from the plurality of mesas Mand the reflective electrodes 30 by the lower insulation layer 31.

Each of the openings of the current spreading layer 33 has a larger areathan the openings of the lower insulation layer 31 to prevent thecurrent spreading layer 33 from being connected to the reflectiveelectrodes 30.

The current spreading layer 33 is formed substantially over the entiretyof the upper area of the substrate 31 excluding the openings. Thisstructure allows electric current to easily spread through the currentspreading layer 33. The current spreading layer 33 may include a highlyreflective metal layer such as an Al layer. The highly reflective metallayer may be formed on a bonding layer such as a Ti, Cr or Ni bondinglayer. In addition, a protective layer having a single layer ormultilayer structure of Ni, Cr, Au, and the like may be formed on thehighly reflective metal layer. The current spreading layer 33 may have,for example, a multilayer structure of Ti/Al/Ti/Ni/Au.

According to various embodiments, the light emitting diode chip has anupper insulation layer 35 formed on the current spreading layer 33. Theupper insulation layer 35 has an opening through which the currentspreading layer 33 is exposed and openings through which the reflectiveelectrodes 30 are exposed.

The upper insulation layer 35 may be formed of an oxide insulationlayer, a nitride insulation layer, a combination layer or alternatinglayers of these insulation layers, or may be formed using polymers suchas polyimides, Teflon, Parylene, and the like.

A first electrode pad 37 a and a second electrode pad 37 b are formed onthe upper insulation layer 35. The first electrode pad 37 a is connectedto the current spreading layer 33 through the opening of the upperinsulation layer 35, and the second electrode pad 37 b is connected tothe reflective electrodes 30 through the openings of the upperinsulation layer 35. The first and second electrode pads 37 a, 37 b maybe used as pads for connection of bumps or for SMT in order to mount thelight emitting diode on the circuit board.

The first and second electrode pads 37 a, 37 b may be formed together bythe same process, for example, by photolithography and etching or by alift-off process. The first and second electrode pads 37 a, 37 b mayinclude, for example, a bonding layer such as Ti, Cr or Ni, and a highlyconductive metal layer such as Al, Cu, Ag or Au. Each of the first andsecond electrode pads 37 a, 37 b may be formed to have both ends thereofplaced on the same plane, whereby the light emitting diode chip may beflip-chip bonded to a conductive pattern, which is formed to the sameheight on the circuit board.

Then, the growth substrate 112 is divided into individual light emittingdiode chip units, thereby completing fabrication of light emitting diodechips. The growth substrate 112 may be removed from the light emittingdiode chips before or after being divided into the individual lightemitting diode chip units.

As described above, the light emitting diode chip 111 mounted on thecircuit board by direct flip-chip bonding can realize high efficiencyand a small structure, as compared with a general package type lightemitting device.

FIG. 3 is an exploded perspective view of a display including a smallbacklight unit, FIG. 4 is a sectional view of the display taken alongline II-II′ of FIG. 3, and FIG. 5 is a perspective view of a lightsource module of FIG. 3.

As shown in FIG. 3 to FIG. 5, the display includes a display panel (DP)on which images are displayed, a backlight unit (BLU) disposed at a rearside of the display panel (DP) and emitting light, and a light shieldingtape (ST) bonding the display panel (DP) to the backlight unit (BLU)while preventing light leakage at an edge of the display.

The display panel (DP) includes a color filter substrate and a thin filmtransistor substrate assembled to each other to maintain a uniform cellgap therebetween while facing each other. According to type, the displaypanel (DP) may further include a liquid crystal layer between the colorfilter substrate and the thin film transistor substrate. The displaypanel (DP) may be provided at one side thereof with a drive interface(DI) for driving the panel.

Although not shown in detail in the drawings, the thin film transistorsubstrate includes a plurality of gate lines and data lines crossingeach other to define pixels therebetween, and a thin film transistorplaced in each of crossing areas between the gate lines and the datalines to be connected to a pixel electrode disposed in each of thepixels in one-on-one correspondence. The color filter substrate includesRGB color filters corresponding to the respective pixels, a black matrixdisposed along the periphery of the substrate and shielding the gatelines, data lines and thin film transistors, and a common electrodecovering all of these components. Here, the common electrode may beformed on the thin film transistor substrate.

The backlight unit (BLU) supplying light to the display panel (DP)includes a light guide plate 160 that converts point light into surfacelight, a light source module 100 disposed on at least one side of thelight guide plate 160, optical sheets 150 placed on the light guideplate 160, and a reflective sheet 170 placed under the light guide plate160.

The light source module 100 includes a circuit board 140, a lightemitting device 110, and a reflective portion 130.

The light emitting device 110 is mounted on the circuit board 140 to beseparated a constant distance from other light emitting devices. Thelight emitting device 110 emits light through three side surfacesthereof adjoining the reflective layer 121 (see FIG. 1).

The reflective portion 130 is placed on the circuit board 140 andincludes an accommodation recess 131 that accommodates the lightemitting device 110 therein. The reflective portion 130 exposes an uppersurface of the light emitting device 110 through the accommodationrecess 131, which has a light discharge portion 137 open at one sidethereof. Here, the light discharge portion 137 corresponds to one openside of the accommodation recess 131 and is defined as a region throughwhich light is discharged outside.

The accommodation recess 131 includes inner surfaces 133, 135, whichadjoin the light discharge portion 137 and have a coplanar structurewith side surfaces of the light emitting device 110. That is, the innersurfaces 133, 135 are coplanar with the corresponding side surfaces ofthe light emitting device 110 and serve to reflect light emitted fromthe side surfaces of the light emitting device 110 towards the lightdischarge portion 137.

The reflective portion 130 may be directly formed on the circuit board140 by depositing and curing a molding resin, without being limitedthereto. Alternatively, the reflective portion 130 may be placed on thecircuit board 140 via a separate bonding member (not shown). Thereflective portion 130 may have a profile, the height of which variesdepending upon the design of the light emitting device 110. Thereflective portion 130 may have the same or greater height than thelight emitting device 110.

As such, the present disclosure has an advantageous effect in that lightemitted from the light emitting device 110 is reflected towards thelight guide plate 160 by the reflective portion 130 formed on thecircuit board 140, thereby minimizing light loss while allowing light tobe focused in a desired direction.

In addition, the present disclosure can omit a separate structure suchas a reflective housing for focusing light on the light guide plate 160by the structure of the reflective portion 130 integrally formed withthe circuit board 140, thereby improving assembly efficiency whileadvantageously enabling reduction in thickness of the light sourcemodule 100 and a slim structure of the backlight unit (BLU) togetherwith the light emitting device 110 that has a decreased thickness.

FIG. 6 is a plan view of a light source module 200 according to anaspect of the present invention, and FIG. 7 is a plan view of a lightsource module according to an aspect of the present invention.

Referring to FIGS. 6 and 7, light source modules 200, 300 have the samestructure as that of the light source module 100 except for reflectiveportions 230, 330. Thus, the similar components will be denoted by thesame reference numerals and detailed descriptions thereof will beomitted.

In the light source module 200, the reflective portion 230 is placed ona circuit board 140 and includes an accommodation recess 231 thataccommodates a light emitting device 110. The reflective portion 230exposes an upper surface of the light emitting device 110 through theaccommodation recess 231, which has a light discharge portion 237 openat one side thereof. Here, the light discharge portion 237 correspondsto one open side of the accommodation recess 231 and is defined as aregion through which light is discharged outside.

The accommodation recess 231 includes inner surfaces 233, 235, whichadjoin the light discharge portion 237 and have inclined structures thatare symmetrical to each other. That is, the inner surfaces 233, 235 areconfigured to be gradually apart from each other in a direction ofapproaching the light discharge portion 237. The inner surfaces 233, 235serve to reflect light emitted from the side surfaces of the lightemitting device 110 towards the light discharge portion 237.

The reflective portion 230 may be directly formed on the circuit board140 by depositing and curing a molding resin, without being limitedthereto. Alternatively, the reflective portion 230 may be placed on thecircuit board 140 via a separate bonding member (not shown). Thereflective portion 230 may have a profile, the height of which variesdepending upon the design of the light emitting device 110. Thereflective portion 230 may have the same or greater height than thelight emitting device 110.

In the light source module 300, the reflective portion 330 is placed onthe circuit board 140 and includes an accommodation recess 331 thataccommodates the light emitting device 110. The reflective portion 330exposes an upper surface of the light emitting device 110 through theaccommodation recess 331, which has a light discharge portion 337 openat one side thereof. Here, the light discharge portion 337 correspondsto one open side of the accommodation recess 331 and is defined as aregion through which light is discharged outside.

The accommodation recess 331 includes inner surfaces 333, 335, whichadjoin the light discharge portion 337 and have curved structures. Thatis, the inner surfaces 333, 335 are configured to be apart from eachother in a direction of approaching the light discharge portion 337. Theinner surfaces 333, 335 serve to reflect light emitted from the sidesurfaces of the light emitting device 110 towards the light dischargeportion 337.

The reflective portion 330 may be directly formed on the circuit board140 by depositing and curing a molding resin, without being limitedthereto. Alternatively, the reflective portion 330 may be placed on thecircuit board 140 via a separate bonding member (not shown). Thereflective portion 330 may have a profile, the height of which variesdepending upon the design of the light emitting device 110. Thereflective portion 130 may have the same or greater height than thelight emitting device 110.

FIG. 8 is a perspective view of a light emitting device 410 according toan aspect of the present invention and FIG. 9 is a plan view of a lightsource module 500 including the light emitting device of FIG. 8.

Referring to FIGS. 8 and 9, the light source module 500 includes a lightemitting device 410, which includes at least two light emitting diodechips 410 a, 410 b.

A wavelength conversion layer 420 covers the at least two light emittingdiode chips 410 a, 410 b and a reflective layer 421 covers an uppersurface and one side surface of the wavelength conversion layer 420.

Herein, the light emitting device 410 is illustrated as including twolight emitting diode chips 410 a, 410 b. However, it should beunderstood that the present invention is not limited thereto, and thenumber of light emitting diode chips 410 a, 410 b may be changed.

In the light source module 500, the light emitting device 410 includingthe at least two light emitting diode chips 410 a, 410 b, and areflective portion 530 are placed on a circuit board 140.

The reflective portion 530 includes an accommodation recess 531 thataccommodates the light emitting device 410 therein. The reflectiveportion 530 exposes an upper surface of the light emitting device 410through the accommodation recess 531, which has a light dischargeportion 537 open at one side thereof. Here, the light discharge portion537 corresponds to one open side of the accommodation recess 531 and isdefined as a region through which light is discharged outside.

The accommodation recess 531 includes inner surfaces 533, 535, whichadjoin the light discharge portion 537 and have inclined structures.That is, the inner surfaces 533, 535 are configured to be spaced apartfrom each other in a direction of approaching the light dischargeportion 537. The inner surfaces 533, 535 serve to reflect light emittedfrom the side surfaces of the light emitting device 410 towards thelight discharge portion 537.

The reflective portion 530 may be directly formed on the circuit board140 by depositing and curing a molding resin, without being limitedthereto. Alternatively, the reflective portion 530 may be placed on thecircuit board 140 via a separate bonding member (not shown). Thereflective portion 530 may have a profile, the height of which variesdepending upon the design of the light emitting device 410. Thereflective portion 530 may have the same or greater height than theheight of the light emitting device 410.

In the light source module 500, the reflective portion 530 is formed toenclose the light emitting device 410 on the circuit board 140, therebyallowing light to be focused towards one side of the light source module500.

FIG. 10 is a perspective view of a light source module 600 according toan aspect of the present invention and FIG. 11 is a sectional view of adisplay including the light source module of FIG. 10.

Referring to FIGS. 10 and 11, light source module 600 includes a circuitboard 140, a light emitting device 610, a reflection cover 690, and areflective portion 130.

The light source module 600 according to this aspect has the samestructure as that of the light source module 100 (see FIG. 5) except forthe light emitting device 610 and the reflection cover 690. Thus, thesimilar components as those of the first embodiment will be denoted bythe same reference numerals and detailed descriptions thereof will beomitted.

At least one light emitting device 610 is mounted on the circuit board140 to be separated a constant distance from other light emittingdevices. The light emitting device 610 emits light through an uppersurface and three side surfaces thereof adjoining the reflective layer621. That is, the reflective layer 621 is placed at one side of thelight emitting device 610.

The reflection cover 690 and the reflective portion 130 serve to reflectlight emitted from the light emitting device 610. The reflection cover690 is placed on the reflective portion 130. More specifically, thereflection cover 690 covers the reflective portion 130 whichaccommodates the light emitting device 610. Namely, the reflection cover690 can reflect light emitted through the upper surface of the lightemitting device 610.

The reflective portion 130 may be directly formed on the circuit board140 by depositing and curing a molding resin, without being limitedthereto. Alternatively, the reflective portion 130 may be placed on thecircuit board 140 via a separate bonding member (not shown). Thereflective portion 130 may have a profile, the height of which variesdepending upon the design of the light emitting device 610. Thereflective portion 130 may have the same or greater height than thelight emitting device 610.

The display including the light source module 600 includes a displaypanel (DP) and a backlight unit (BLU).

The backlight unit (BLU) includes a light guide plate 660 which convertspoint light into surface light, a light source module 600 disposed on atleast one side of the light guide plate 660, optical sheets 150 placedon the light guide plate 660, and a reflective sheet 170 placed underthe light guide plate 660.

The light guide plate 660 has a structure, one side of which adjacentthe light emitting device 610 is thicker than a light exit area thereof.Specifically, the light guide plate 660 has an upper surface of astepped structure. The stepped structure includes an inclined surfacebetween a light incident area and the light exit area. The steppedstructure of the light guide plate 660 is advantageous in providing aslim structure.

The light source module 600 is disposed on at least one side of thelight guide plate 660 to be parallel thereto. The light source module600 has a structure in which the circuit board 140 contacts an uppersurface of the reflective sheet 170.

The reflection cover 690 covers the reflective portion 130 and mayextend to an upper surface of the light incident area. Although thereflection cover 690 is illustrated as covering the reflective portion130 while extending to the upper surface of the light incident area, itshould be understood that the present invention is not limited theretoand the reflection cover 690 may also extend to the inclined surface ofthe light guide plate 660.

As such, the present invention has an advantageous effect in that lightemitted from the light emitting device 610 is reflected towards thelight guide plate 660 by the reflective portion 130 formed on thecircuit board 140 and the reflection cover 690 placed on the reflectiveportion 130, thereby minimizing light loss while allowing light to befocused in a desired direction.

In addition, the present invention can omit components such as areflective housing and the like by providing a simplified structure,which includes the reflective portion 130 integrally formed on thecircuit board 140 and the reflection cover 690 placed on the reflectiveportion 130, thereby improving assembly efficiency while advantageouslyenabling reduction in thickness of the light source module and a slimstructure of the backlight unit (BLU) together with the light emittingdevice 610 which has a decreased thickness.

FIG. 12 is a plan view of a light source module according to an aspectof the present invention.

As shown in FIG. 12, the display has the same configuration as that ofthe display according to FIG. 11 except for a light source module. Thus,the similar components as those of FIG. 11 will be denoted by the samereference numerals and detailed descriptions thereof will be omitted.

In the light source module, a circuit board 140 is directed towards adisplay panel (DP) and an upper surface of a reflective portion 130contacts a reflective sheet 170. The circuit board 140 is provided atone side thereof with the reflective portion 130 and a light emittingdevice 610, and provided at the other side thereof with a reflectioncover 790.

The reflection cover 790 may cover the circuit board 140 while extendingto the upper surface of the light incident area of the light guide plate660. Although the reflection cover 790 is illustrated as covering thecircuit board 140 while extending to the upper surface of the lightincident area, it should be understood that the present invention is notlimited thereto and the reflection cover 790 may also extend to theinclined surface of the light guide plate 660.

As such, the present invention has an advantageous effect in that lightemitted from the light emitting device 610 is reflected towards thelight guide plate 660 by the reflection cover 790 formed on the circuitboard 140, thereby minimizing light loss while allowing light to befocused in a desired direction.

In addition, the present invention can omit components of a typicalbacklight unit, such as a reflective housing and the like, by providinga simplified structure, which includes the reflective portion 130integrally formed with one side of the circuit board 140 and thereflection cover 790 placed on the other side of the circuit board 140,thereby improving assembly efficiency while advantageously enablingreduction in thickness of the light source module and a slim structureof the backlight unit (BLU) together with the light emitting device 610which has a decreased thickness.

FIG. 13 and FIG. 14 are an exploded perspective view of a displayincluding a backlight unit according to an aspect of the presentinvention.

Referring to FIGS. 13 and 14, the display devices include the samecomponents as FIG. 11 except for a reflector 890, 990 and a reflectivesheet 870. Thus, the similar components will be denoted by the samereference numerals, and detailed descriptions thereof will be omittedexcept for the reflector 890, 990.

One side surface of the light emitting device 610 faces a light in alight incident face of the light guide plate 660. Here, the lightincident face may be defined as one side surface of the light guideplate 660, through which light emitted from the light emitting device610 enters the light guide plate 660.

The reflector 890, 990 is disposed on the light emitting device 610 andthe circuit board 140. The reflector 890, 990 comprises a curvedstructure or in an inclined structure. The reflector 890, 990 includesone side surface to contact a portion of the upper surface of thecircuit board 140 and the other side surface to contact a portion of theside surface of light guide plate 660. That is, the first reflector mayhave the one side surface facing the portion of the upper surface of thecircuit board 140, the other side surface facing the portion of the sidesurface of light guide plate 660. The reflector 890, 990 may be preparedby coating a reflective material onto a surface of a base layer, or maybe formed of a base layer composed of a reflective material. Inaddition, the reflector 890, 990 may further include an adhesivematerial formed on the surface of the base layer. The reflective sheet870 is disposed under the light guide plate 660.

According to various embodiments, light emitted from the light emittingdevice 610 can be incident on the light guide plate 660 without loss dueto the reflector 890, 990 enclosing the portion of the other surface ofthe circuit board 140 and the one side surface of the light emittingdevice 610.

Although some exemplary embodiments have been described herein, itshould be understood that the present invention is not limited tocertain embodiments. In addition, some features of a certain embodimentmay also be applied to other embodiments in the same or similar wayswithout departing from the spirit and scope of the present invention asset forth in the claims.

What is claimed is:
 1. A light source module comprising: a circuitboard; a light emitting device mounted on the circuit board by flip-chipbonding or surface mount technology (SMT); and a reflective portiondisposed on the circuit board and enclosing the light emitting device.2. The light source module of claim 1, wherein the light emitting devicecomprises a light emitting diode chip, a wavelength conversion layercovering the light emitting diode chip, and a reflective layer coveringa portion of the wavelength conversion layer; and wherein the reflectivelayer exposes at least one side surface of the wavelength conversionlayer.
 3. The light source module of claim 1, wherein the light emittingdevice comprises at least two light emitting diode chips, a wavelengthconversion layer covering the light emitting diode chips, and areflective layer covering a portion of the wavelength conversion layer;and the reflective layer exposes at least one side surface of thewavelength conversion layer.
 4. The light source module of claim 1,wherein the reflective portion comprises an accommodation recessaccommodating the light emitting device.
 5. The light source module ofclaim 4, wherein the reflective portion comprises inner surfaces atleast partially defined by the accommodation recess, the accommodationrecess exposing an upper surface of the light emitting device and beingopen at one side thereof to have a light discharge portion, throughwhich light is discharged outside the light source module.
 6. The lightsource module of claim 5, wherein the inner surfaces have a coplanarstructure with side surfaces of the light emitting device.
 7. The lightsource module of claim 5, wherein the inner surfaces have an inclinedstructure.
 8. The light source module of claim 5, wherein the innersurfaces have a curved structure.
 9. The light source module of claim 1,wherein the light emitting device has the same height as or a lowerheight than the height of the reflective portion.
 10. The light sourcemodule of claim 1, further comprising a reflection cover placed on thelight emitting device and covering the reflective portion.
 11. Abacklight unit comprising: a light guide plate; and a light sourcemodule disposed on at least one side of the light guide plate. whereinthe light source module comprising a circuit board, at least one lightemitting device mounted on the circuit board by flip-chip bonding orsurface mount technology (SMT), and a reflective portion formed on thecircuit board and enclosing the light emitting device.
 12. The backlightunit of claim 11, wherein the light emitting device comprises a lightemitting diode chip, a wavelength conversion layer covering the lightemitting diode chip, and a reflective layer covering a portion of thewavelength conversion layer, wherein the reflective layer exposes atleast one side surface of the wavelength conversion layer.
 13. Thebacklight unit of claim 11, wherein the light emitting device comprisesat least two light emitting diode chips, a wavelength conversion layercovering the at least two the light emitting diode chips, and areflective layer covering a portion of the wavelength conversion layer;and wherein the reflective layer exposes at least one side surface ofthe wavelength conversion layer.
 14. The backlight unit of claim 11,wherein the reflective portion comprises an accommodation recessaccommodating the light emitting device.
 15. The backlight unit of claim14, wherein the reflective portion comprises inner surfaces at leastpartially defined by the accommodation recess, the accommodation recessexposing an upper surface of the light emitting device and being open atone side thereof facing the light guide plate to have a light dischargeportion, through which light is discharged outside.
 16. The backlightunit of claim 15, wherein the inner surfaces have a coplanar structurewith side surfaces of the light emitting device.
 17. The backlight unitof claim 15, wherein the inner surfaces have an inclined structure. 18.The backlight unit of claim 15, wherein the inner surfaces have a curvedstructure.
 19. The backlight unit of claim 11, wherein the lightemitting device has the same height as or a lower height than the heightof the reflective portion.
 20. The backlight unit of claim 11, furthercomprising a reflection cover placed on the light emitting device andcovering the reflective portion.
 21. The backlight unit of claim 11,wherein the reflective portion is a curved structure or an inclinedstructure.
 22. The backlight unit of claim 11, further comprising: areflective sheet disposed under the light guide plate and parallel tothe circuit board.